Thanks for your input.
I must say what you say is in line with my observations as an FT with more than a few years of teaching experience here in China.
As it happens, I don't have a work visa, lucky me! That said, I should point out that my former colleague had one. Even so, he was cheated out of his holiday salary too, and received zilch as travel allowance for his mid-contract holiday break, just like me. I think it's worth mentioning this here to illustrate that when it comes to dishonesty, this school's actions are not determined by one's visa type.
By the way, the FAO here will really, really be in the lurch if I can get a job offer elsewhere fast. You see, my former colleague's replacement won't arrive until one week from now. At present, I'm teaching my classes from last semester, whereas his (or her) classes are awaiting his (overdue) arrival.
Please, please let me land a job fast! I'm keeping my fingers X'ed!
Before finishing this post, I'll reveal that the school's name is M**** High School of Sichuan, and the FAO's initials are VZ, V for his English forename, and Z for his Chinese surname. You've been warned! I'll post the full details when I'm outahere, as the last thing I need is to be the focus of undeserved Chinese vindictiveness here.